Absorption refrigerating system having pump means circulating absorbent and refrigerant



Jan. 10, 1967 R. P. NOVAK ETAL ABSORPTION REFRIGERATING SYSTEM HAVINGPUMP MEANS CIRCULATING ABSORBENT AND REFRIGERANT Filed June 16, 1965 5Sheets-Sheet l ATTORNEYS Jan. 10, 1967 ov ETAL 3,296,823

ABSORPTION REFRIGERATING SYSTEM HAVING PUMP MEANS GIRCULATING ABSORBENTAND REFRIGERANT Filed June 16, 1965 5 Sheets-Sheet 2 FIGS 1N VEN'IURSROBERT P. NOVAK JAMES M. PORTER AT TOR NEYS Jan. 10, 1967 R. P. NOVAKETAL 3,296,823

ABSORPTION REFRIGERATING SYSTEM HAVING PUMP MEANS CIRCULATING ABSORBENTAND REFRIGERANT Filed June 16, 1965 5 Sheets-Sheet s I N V EN '1 0R8ROBERT P. NOVAK JAMES M. PORTER 7 m? v QMM ATTORNEYS States Patent@flice 3,296,823 Patented Jan. 10, 1967 3,296,823 ABSORPTIONREFRIGERATENG SYSTEM HAVllN G PUMP MEANS CHRCULATTNG ABSORBENT ANDREFRIGERANT Robert P. Novak, Mindoro, and James M. Porter, La Crosse,Wis, assignors to The Trane Company, La Crosse, Wis, a corporation ofWisconsin Filed June 16, 1965, Scr. No. 464,359 8 Claims. (Cl. 62-476)This invention relates to absorption refrigerating systems and moreparticularly to an absorption refrigerating system including pump meansfor circulating fluids in the system. In general, systems of this typehave interior spaces which are less than atmospheric pressure duringoperation. It is desirable to avoid the use of running seals between theinterior of the pump and the atmosphere, because such seals often permitair to enter the system in spite of attempts to design seals to preventleakage. The presence of air in the system results in reduced efliciencyand the air must be removed by a purge system.

The use in an absorption refrigerating system of hermetically sealedpumps has been shown in US. Patent No. 2,983,117 issued to P. Edberg etal. However in such systems, there is some danger of overheating thesolution pump motors in the event of failure of the evaporator pumpwhich supplies refrigerant for lubricating and cooling these motors.

It is therefore an object of this invention to provide a pump forpumping a plurality of fluids in which the pump is driven by a singlemotor.

It is another object of this invention to provide a motor driven pumpfor pumping a plurality of fluids in which one of the fluids pumped iscirculated to cool and lubricate the motor and the pump.

It is another object of the invention to provide a pump and a drivingmotor secured in hermetically sealed relationship with each other.

It is another object of this invention to provide a pump having arotating seal between the pump and the motor to permit removal of themotor without opening the pump or the absorption system to theatmosphere.

It is another object of the invention to provide a pump having solutionimpellers in back-to-back relationship at one end and a refrigerantimpeller at the other end with a driving motor at the end having therefrigerant impeller so that if there is leakage into the motor thefluid leaked will berefrigerant and not absorbent solution which couldcause corrosion in the motor.

It is another object of the invention to reduce the thrust forces of thepump shaft by mounting the solution pumps in back-to-back relationshipand providing a balancing piston eifect on the evaporator pump so thatthere is a reduced thrust of the pump shaft on the motor shaft.

It is another object of the invention to provide a thrust bearing on themotor shaft to absorb the combined thrust of the pump shaft and themotor shaft.

It is another object of the invention to provide means for lubricatingand cooling the pump and the motor from a fluid source separate from theabsorption machine.

Other objects and advantages of this invention will become apparent asthe specification proceeds to describe the invention with reference tothe accompanying drawing in which:

FIGURE 1 is a diagrammatic sectional view of the absorptionrefrigerating system including the fluid circulating system;

FIGURE 2 is an end view of the pump;

FIGURE 3 is a sectional view taken on line 3--3 of FIGURE 2; and

FIGURE 4 is a longitudinal sectional view of the motor taken on line 3-3of FIGURE 2.

Referring now to FIGURE 1, the absorption system shown is of the typehaving a single shell 10, a partition 11 separating a high pressurechamber containing a condenser 12 and a generator 14 from a low pressurechamber containing an evaporator 16 and an absorber 18. It should beunderstood that other arrangements might be used; for instance, thegenerator 14 and the condenser 12 might be in one shell and the absorber18 and the evaporator 16 might be in a second shell with conduitstherebetween for conducting fluids.

Various combinations of refrigerant and absorbent may be used. Asolution of lithium bromide and water has been found to be highlysatisfactorily for use.

The absorber 18 has a coil 20 supplied with cooling fluid from a source22 to remove the heat from the absorber. This cooling fluid is conductedby a conduit 24 to a cooling coil 26 in the condenser 12 and the coolingfluid leaves the machine through a conduit 28. The cooling coil 26 inthe condenser 12 removes the heat from and condenses the refrigerantvapor in the condenser.

The generator 14 has a heating coil 3t supplied with heating fluid froma source 32. The heating fluid is discharged from the coil 3th through aconduit 34. The coil 3i heats the absorbent solution in the generator 14causing it to boil and force refrigerant vapor into the condenser 12.The condensed refrigerant in the condenser 12 flows through an opening36 into the evaporator 16. The absorbent solution in the absorber 18reduces the pressure in the absorber i8 and in the evaporator 16 by theabsorption of refrigerant vapor, thus causing the refrigerant in theevaporator 16 to boil. A low temperature is thus maintained in theevaporator 16.

Evaporator 16 has a coil 37. Fluid from a refrigerating load such as anair conditioning system enters coil 37 through a conduit 38. This fluidis reduced in temperature in the coil 37 and returns to therefrigerating load through conduit 39.

The liquid refrigerant in the evaporator 16 flows through a conduit 40to a sump 41 and thence through conduit 42 to a pump indicated generallyby numeral 43. Pump 43 is driven by a motor indicated generally bynumeral 44. The liquid refrigerant is discharged by pump 43 throughconduit 45 from which it flows through nozzles 46 into the evaporator16.

Dilute solution flows from absorber 18 through conduit 48 to pump 43.The dilute solution is discharged by pump 43 through conduit 50 whichconducts the dilute solution to heat exchanger 52 from which it flowsthrough conduit 54 to the generator 14.

Concentrated solution flows from the generator 14 through conduit 56 andthence through heat exchanger 52 from which it flows through conduit 58to conduit 60.

Dilute solution flows from absorber 18 through conduit 62 and thenceinto conduit 60 to form, with the solution from conduit 58, a solutionof intermediate concentration which enters the pump 43 and is dischargedthereby through conduit 62 which discharges the intermediate solutioninto the absorber through nozzles 63.

Pump 43 has a pump body 64. A hearing housing 65 having a bearing 66 ismounted on the body 64 at one end and a bearing housing 67 having abearing 68 is mounted on the pump body 64 at its other end. Bearings 66and 68 have helical grooves 69 and '70 respectively for conducting theliquid which lubricates and cools the bearings. A shaft 72 is rotatablymounted in the bearings 66 and 68.

A refrigerant impeller 73 is mounted on shaft 72 to rotate therewith.Pump 43 has an inlet passageway '74 in fluid flow communication withconduit 42 and impeller 73. A discharge passageway 75 is in fluid flowcommunication with impeller 73 and conduit 45. Impeller 73 has holes 76which conduct refrigerant from a chamber 71 at 3 the back side of theimpeller to provide a balancing piston effect and reduce the thrust ofimpeller 73 during operation.

An impeller 77 is mounted on shaft 72 to rotate therewith. Pump 43 hasan inlet passageway 78 in fluid flow communication with conduit 60 andimpeller 77. A discharge passageway 79 is in fiuid flow communicationwith impeller 77 and conduit 62.

An impeller 80 is mounted on shaft 72 to rotate therewith. Pump 43 hasan inlet passageway 82 in fluid flow communication with conduit 48 andimpeller 80. A discharge passageway 83 is in fluid flow communicationwith impeller 80 and conduit 50.

A rotating seal 84 is mounted on shaft 72 to prevent leakage betweenbearing housing 65 and inlet passageway 78.

A rotating seal 86 is mounted on shaft 72 to prevent leakage betweenchamber 71 and inlet passageway 82.

A rotating seal 88 is mounted on shaft 72 to prevent leakage betweenbearing housing 67 and inlet passageway 74.

The motor 44 has a frame comprising casing 89 and bearing housings 90and 93. Bearing housing 90 has a bearing 92 and bearing housing 93 has abearing 94, A shaft 95 is rotatably mounted in bearings 92 and 94. Adrive coupling 91 is secured to pump shaft 72 and is in splinedengagement with motor shaft 95. A thrust hearing member 96 is mounted onshaft 95 and is supported by the bearing housing 93. The thrust bearing96 is of the well known Kingsbury type having pivoted shoes. A motorrotor 97 is mounted on shaft 95 within a motor stator 98.

For conducting refrigerant liquid to the pump 43 and motor 44 forcooling and lubricating these parts, a conduit 99 extends from thedischarge passageway 75. The refrigerant liquid flows through conduit101 to motor 44. The refrigerant liquid then flows through a helicalgroove 102 in bearing 94, thence through thrust bearing 96 and thenthrough the gap 103 between rotor 97 and stator 98. From the gap 103 thefluid flows through a helical groove 104 in bearing 92 and into thespace 105 between bearing housings 67 and 90. Some refrigerant liquidflows through helical groove 70 in bearing 68. From space 105 therefrigerant liquid flows through conduits 106 and 107 to the inletchamber 74 and of the pump 43.

Refrigerant liquid from conduit 99 also'flows through conduit 108 toconduit 109 and thence to the helical groove 69 of bearing 66. Frombearing 66 the liquid flows through conduit 110 and thence throughconduit 111 to conduit 107 from which it flows to inlet chamber 74 ofpump 43.

There may be times when there is insufiicient refrigerant forlubricating and cooling pump 43 and motor 44. For this reason, provisionis made for using an external source of water such as city water forcooling and lubricating the pumps. In order to accomplish this, weprovide a valve 112 in conduit 99 and a valve 113 in conduit 107 to shutoff the flow in these conduits. Valve 114 is connected to a pressurizedsource of water external to the system and valve 115 controls the returnflow to the source or to waste.

When it is desired to operate the machine using an external source ofwater for lubricating and cooling the pump 43 and the motor 44, valves112 and 113 are closed and valves 114 and 115 are opened. The flow isthen as indicated by the dash line arrows. From valve 114 a portion ofthe flow is through conduit 109 to hearing 66 and then through conduit110 and valve 115. The other portion of the flow from valve 114 issuccessively through conduits 108, 101, motor 44, conduits 106, 111 andvalve 115.

The uppermost portions of discharge chambers 79 and 83 are provided withhand valves 116 and 117 respectively. During operation of the systemthese valves are in closed position. However when it is desired to openpump 43 to service the interior parts, valves 116 and 117 may be openedto allow air to enter the pump and displace absorbent solution in thepump.

It is to be noted that impellers 77 and have equal outside diameters atthe inlet and the discharge. This simplifies the machining of thehousing and it makes it possible to remove these impellers 77 and 80from the housing by removing the bearing housing 65. The impellers 77and 80 may be removed without removing the shaft 72.

Impeller 73 is similarly constructed, and it can be removed by firstremoving the motor 44 and the bearing housing 67,

Although we have described specific embodiments of our invention, wecontemplate that various modifications may be made without departingfrom the scope or spirit of our invention and we desire to be limitedonly by the claims.

We claim:

1. In an absorption refrigerating system having a refrigerant and anabsorbent, the combination of an absorber, an evaporator, a generator, acondenser and a pump to circulate refrigerant and absorbent in saidsystem, said pump having a shaft rotatably mounted therein, a motordrivingly connected to said shaft, a first impeller mounted on saidshaft, conduit for conducting absorbent from said absorber to the inletof said first impeller, conduit for conducting absorbent from the outletof said first impeller to said generator, a second impeller mounted onsaid shaft in adjacent back-to-back relationship with said firstimpeller, conduit for conducting absorbent from a first portion of saidabsorber to the inlet of said second impeller, conduit for conductingabsorbent from the outlet of said second impeller to a second portion ofthe absorber, a third impeller mounted on said shaft, conduit forconducting refrigerant from a first portion of the evaporator to theinlet of said third impeller and conduit for conducting refrigerant fromthe outlet of said third impeller to a second portion of the evaporator.

2. In an absorption refrigerating system having a refrigerant and anabsorbent, the combination of an absorber, an evaporator, a generator, acondenser, and a pump to circulate refrigerant and absorbent in saidsystem, said pump having a shaft rotatably mounted therein, a motordrivingly connected to said shaft, a first impeller mounted on saidshaft, conduit for conducting absorbent from said absorber to the inletof said first impeller, conduit for conducting absorbent from the outletof said first impeller to said generator, a second impeller mounted onsaid shaft in adjacent back-to-back relationship with said firstimpeller, conduit for conducting absorbent from a first portion of saidabsorber to the inlet of said second impeller, conduit for conductingabsorbent from the outlet of said second impeller to a second portion ofthe absorber, a third impeller mounted on said shaft, conduit forconducting refrigerant from a first portion of the evaporator to theinlet of said third impeller, and conduit for conducting refrigerantfrom the outlet of said third impeller to a second portion of saidevaporator, said third impeller having means for conducting refrigerantfrom the back of said third impeller to the inlet of said third impellerto reduce the thrust of said third impeller.

3. In an absorption refrigerating system having a refrigerant and anabsorbent, the combination of an absorber, an evaporator, a generator, acondenser and a pump to circulate refrigerant and absorbent in saidsystem, said pump comprising an elongated body, a pump shaft, bearingsin said body adjacent opposite ends thereof for rotatably supportingsaid pump shaft in said body, a first centrifugal impeller mounted onsaid shaft adjacent one end of said body, conduit for conductingabsorbent from said absorber to the inlet of said first impeller,conduit for conducting absorbent from the outlet of said first impellerto said generator, a second centrifugal impeller mounted on said pumpshaft in adjacent back-to-back relationship with said first impeller,conduit for conducting absorbent from a first portion of said absorberto the inlet of said second impeller, conduit for conducting absorbentfrom the outlet of said second impeller to a second portion of saidabsorber, a third impeller mounted on said shaft adjacent the other endof said body from said first end, conduit for conducting refrigerantfrom a first portion of said evaporator to the inlet of said thirdimpeller and conduit for conducting refrigerant from the outlet of saidthird impeller to a second portion of said evaporator, a motor framesecured to said other end of said pump body, a motor shaft, meansrotatably mounting said motor shaft on said motor frame, a thrustbearing on said motor frame for axially supporting said motor shaft,means coupling said pump shaft to said motor shaft for driving said pumpshaft from said motor shaft and means on said pump shaft and said motorshaft for transferring the thrust of said pump shaft to said motorshaft.

4. In an absorption refrigerating system according to claim 3 in whichthe outlet of said third impeller is arranged longitudinally of saidbody between the inlet of said third impeller and the outlet of saidsecond impeller, means for conducting refrigerant from the back of saidthird impeller to the inlet of said third impeller to reduce the thrustof said third impeller.

5. In an absorption refrigerating system having a refrigerant and anabsorbent, the combination of an absorber, an evaporator, a generator, acondenser and a pump to circulate refrigerant and absorbent in saidsystem, said pump comprising an elongated body, a pump shaft, a firstshaft bearing adjacent one end of said body for rotatably supportingsaid pump shaft in said body, a first centrifugal impeller mounted onsaid shaft adjacent said first shaft bearing, a second impeller mountedon said shaft adjacent said first impeller, first conduit for conductingabsorbent from said absorber to the inlet of one of said first andsecond impellers and from the outlet of said one of said first andsecond impellers to said generator, second conduit for conductingabsorbent from a first portion of said absorber to the inlet of thesecond of said first and second impellers, and from the outlet of saidsecond of said first and second impellers to a second portion of saidabsorber, a third centrifugal impeller mounted on said shaft, thirdconduit for conducting refrigerant from a first portion of theevaporator to the inlet of said third impeller, and fourth conduit forconducting refrigerant from the outlet of said third centrifugalimpeller to a second portion of said evaporator, a second shaft bearingadjacent the other end of said body, a motor frame secured to said otherend of said body, a motor shaft, motor bearings rotatably mounting saidmotor shaft on said motor frame, a thrust bearing on said motor framefor axially supporting said motor shaft, means coupling said pump shaftto said motor shaft for driving said pump shaft from said motor shaft,means on said pump shaft and said motor shaft for transferring thethrust of said pump shaft to said motor shaft, and a rotating seal onsaid pump shaft between the third conduit and said second shaft bearing.

6. In an absorption refrigeration system having a refrigerant andabsorbents, the combination of an absorber, an evaporator, a condenser,a generator and a pump in a closed system, said pump comprising anelongated body, a pump shaft, a first shaft bearing adjacent one end ofsaid body for rotatably supporting said pump shaft in said body, saidbody having adjacent said one end of a first inlet passageway and afirst discharge passageway, a first centrifugal impeller mounted on saidpump shaft in fluid communication with said first inlet passageway andsaid first discharge passageway for circulating a first absorbent, saidbody having a second inlet passageway and a second discharge passageway,a second centrifugal impeller mounted on said pump shaft in fluidcommunication with said second inlet passageway and said seconddischarge passageway for circulating a second absorbent, said bodyhaving at the other end from said one end a third inlet passageway and athird discharge passageway for refrigerant, a third centrifugal impellermounted on said pump shaft in fluid communication with said third inletpassageway and said third discharge passageway for circulatingrefrigerant, a second shaft bearing adjacent said other end of saidbody, a motor frame secured to said other end of said pump body, a motorshaft, motor bearings rotatably mounting said motor shaft on said motorframe, a thrust bearing on said motor frame for axially supporting saidmotor shaft, means coupling said pump shaft to said motor shaft fordriving said pump shaft from said motor shaft, means on said pump shaftand said motor shaft for transferring the thrust of said pump shaft tosaid motor shaft, means for conducting water from a source exterior tosaid system over said motor bearings, said thrust bearing and said firstand second bearings to cool and lubricate the same.

7. In an absorption refrigeration system having a refrigerant andabsorbents, the combination of an absorber, an evaporator, a condenser,a generator and a pump in a closed system, said pump comprising anelongated body, a pump shaft, pump shaft bearing means for rotatablysupporting said pump shaft in said body, said body having a first inletpassageway and a first discharge passageway, a first centrifugalimpeller mounted on said pump shaft in fluid communication with saidfirst inlet passageway and said first discharge passageway forcirculating a first absorbent, said body having a second inletpassageway and a second discharge passageway, a second centrifugalimpeller mounted on said pump shaft in fluid communication with saidsecond inlet passageway and said second discharge passageway forcirculating a second absorbent, said body having a third inletpassageway and a third discharge passageway, a third centrifugalimpeller mounted on said pump shaft in fluid communication with saidthird inlet passageway and said third discharge passageway forcirculating refrigerant, a motor frame secured to said pump body, amotor shaft, motor bearing means rotatably mounting said motor shaft onsaid motor frame, means drivingly connecting said pump shaft to saidmotor shaft for driving said pump shaft from said motor shaft and meansfor conducting refrigerant over said pump shaft bearing means and saidmotor bearing means to cool and lubricate the same.

8. In an absorption refrigeration system having a refrigerant andabsorbents, the combination of an absorber, an evaporator, a condenser,a generator and a pump in a closed system, said pump comprising anelongated body, a pump shaft, a first shaft bearing adjacent one end ofsaid body for rotatably supporting said pump shaft in said body, saidbody having adjacent said one end a first inlet passageway and a firstdischarge passageway, a first centrifugal impeller mounted on said pumpshaft in fluid communication with said first inlet passageway and saidfirst discharge passageway for circulating a first absorbent, said bodyhaving a second inlet passageway and a second discharge passageway, asecond centrifugal impeller mounted on said pump shaft in fluidcommunication with said second inlet passageway and said seconddischarge passageway for circulating a second absorbent, said bodyhaving at the other end from said one end a third inlet passageway and athird discharge passageway for refrigerant, a third centrifugal impellermounted on said pump shaft in fluid communication with said third inletpassageway and said third discharge passageway for circulatingrefrigerant, a second shaft bearing adjacent said other end of saidbody, a motor frame secured to said other end of said pump body, a motorshaft, motor bearing means rotatably mounting said motor shaft on saidmotor frame, a thrust bearing on said motor frame for axially supportingsaid motor shaft, means coupling said pump shaft to said motor shaft fordriving said pump shaft from said motor shaft, means on said pump shaftand said motor shaft for transferring the thrust of said pump shaft tosaid motor shaft, means for conducting refrigerant from said thirdimpeller over said motor bearing means, said thrust bearing and saidfirst and second bearings and back to said third inlet passageway tocool and lubricate said motor bearing means, said thrust bear ing, andsaid first and second bearings.

References Cited by the Examiner UNITED STATES PATENTS LLOYD L. KING,Primary Examiner.

1. IN AN ABSORPTION REFRIGERATING SYSTEM HAVING A REFRIGERANT AND ANABSORBENT, THE COMBINATION OF AN ABSORBER, AN EVAPORATOR, A GENERATOR, ACONDENSER AND A PUMP TO CIRCULATE REFRIGERANT AND ABSORBENT IN SAIDSYSTEM, SAID PUMP HAVING A SHAFT ROTATABLY MOUNTED THEREIN, A MOTORDRIVINGLY CONNECTED TO SAIDSHAFT, A FIRST IMPELLER MOUNTED ON SAIDSHAFT, CONDUIT FOR CONDUCTING ABSORBENT FROM SAID ABSORBER TO THE INLETOF SAID FIRST IMPELLER, CONDUIT FOR CONDUCTING ABSORBENT FROM THE OUTLETOF SAID FIRST IMPELLER TO SAID GENERATOR, A SECOND IMPELLER MOUNTED ONSAID SHAFT IN ADJACENT BACK-TO-BACK RELATIONSHIP WITH SAID FIRSTIMPELLER, CONDUIT FOR CONDUCTING ABSORBENT FROM A FIRST PORTION OF SAIDABSORBER TO THE INLET OF SAID SECOND IMPELLER, CONDUIT FOR CONDUCTINGABSORBENT FROM THE OUTLET OF SAID SECOND IMPELLER TO A SECOND PORTION OFTHE ABSORBER, A THIRD IMPELLER MOUNTED ON SAID SHAFT, CONDUIT FORCONDUCTING REFRIGERANT FROM A FIRST PORTION OF THE EVAPORATOR TO THEINLET OF SAID THIRD IMPELLER AND CONDUIT FOR CONDUCTING REFRIGERANT FROMTHE OUTLET OF SAID THIRD IMPELLER TO A SECOND PORTION OF THE EVAPORATOR.